The phone company’s U-Verse television service will start offering an online video streaming service called “U-Verse Screen Pack” for $5 extra a month, available to U-Verse television subscribers, AT&T said today at the Consumer Electronics Show.

The new service will launch with 1,500 mostly older movies, from Sony Pictures Studios and MGM Studios Inc. “among others,” AT&T said. A spokesman said that newer releases as well as TV shows are on the way.

AT&T is entering a crowded space. Aside from Netflix and Amazon.com Inc., several other pay TV operators have launched streaming services Comcast Corp.’s Streampix service lets subscribers stream a variety of movies and TV shows for $4.99 a month Verizon Communications Inc. and Coinstar Inc.’s joint venture dubbed Redbox Instant last month began rolling out its streaming and DVD-rental service, which costs $8 a month Dish Network Corp. has a streaming service for subscribers using the Blockbuster name, which costs $10 a month. Then there’s Hulu, owned by several major entertainment companies.

With Netflix Inc. and Amazon.com Inc. investing heavily in older shows and movies, and in original series, competing in the space requires a hefty investment to license content. Dish Network Corp. executives have said publicly in recent months that the high price of streaming content deals has hobbled Dish’s ability to expand its Blockbuster unit into a Netflix competitor.

AT&T said it plans to expand its streaming library over time. It remains to be seen just how well it can do that, considering the costs.